Bearings for instruments and machines



May 29, 1956 M. BAERMANN BEARINGS FOR INSTRUMENTS AND MACHINES FiledSept. 16, 1953 2 Sheets-Shet 1 Fig.2

Ill/V INVENTOR: Man: BaermcL/m JLJML g M' ATTO ILN E5:

y 29, 1956 M. BAERMANN 2,747,944

BEARINGS FOR INSTRUMENTS AND MACHINES Filed Sept. 16, 1955 2Sheets-Sheet 2 Fig, 4

/ A 34 ,L I \3' I o 6 IN VE NTOR: 35 36 Max Baa/maria wwaw OULNEBS UniteStates Patent '6 BEARINGS FOR INSTRUMENTS AND MACHINES Max Baermann,Bensberg-Wulfshof, Bezirk Koln, Germany Application September 16, 1950,Serial No. 185,233 Claims priority, application Germany September 19,1949 4 Claims. (Cl. 308-40) This invention relates to instruments andmachines having rotary parts, particularly measuring instruments such aselectric counters with vertical shafts or gyrocompasses, turbogenerators, small turbines, ultra centrifuges, etc. The invention isparticularly concerned with magnetically and/or electrostaticallyoperated, substantially frictionless bearings and centering means forthe rotary parts of such instruments and machines. The prior art rotaryshafts of measuring instruments are provided with pointed ends and aresupported at such ends on both sides; it is also possible to employspecial step bearings and collar bearings for such purpose, and wheneverhigh sensitivity is required, and the shifting forces are small, it ispreferred to employ semi-precious stones, including so-called punchedand capped jewels, as bearings.

It was found, however, that a certain amount of friction develops in thebest bearings of this type, and this friction must be overcome by theadjusting forces of the indicating elements of the instruments,resulting in a less precise indication. Furthermore, the precision ofthe instruments is also detriment-ally affected by a lengthy orcontinuous use which results in the wearing out of the bearings.

Other machines provided with rapidly rotating bodies, such as the rotorsof gyro compasses, turbo generators, small turbines, ultra centrifuges,and the like, include a shaft which is usually positioned horizontally,and which must be driven as quickly as possible so that the size of themachine may remain small for a specific output.

Heretofore, however, the highest possible speed of rotation permitted bythe material could not be used in such machines since the usual shaftbearings, such as ball bearings or roller bearings,-were not capable ofwithstanding the strain after a short while.

In the construction of magnetic systems for this purpose it was foundnecessary to avoid an unstable equilibrium as a result of which thesmallest shifting of the system results in a substantial change in themagnetic forces.

An object of the present invention is to provide a bearing for rotaryparts of instruments and machines of the described type wherein magneticand/ or electrostatic forces are utilized to provide a perfectly stableand reliable balancing of the rotary parts.

Another object is to provide a magnetic and/r electrostatic bearing forrotors operated with a high speed.

A further object is to eliminate frictional losses, in shaft bearingswhich are generally quite high in rapidly driven rotors.

Yet another object is to utilize the repelling forces between magnets toprovide a bearing for machines or devices having a horizontallysupported shaft.

A further object of the invention is to eliminate the drawbacks of priorart constructions and to provide a magnetic bearing wherein a stableequilibrium is attained,

2,747,944 Patented May 29, 1956 and wherein the rotating shaft need notfunction in its entirety as a magnet.

Other objects of the present invention will become apparent in thecourse of the following specification.

The objects of the present invention may be realized through theprovision of magnetic bearings provided with magnets upon the rotaryshaft and immovable casing, said magnets being so magnetized that theyrepel each other.

Due to this arrangement of repelling magnets the shaft which is beingsupported is held in place solely by symmetrical, radially directedrepelling forces, thus providing a stable equilibrium in the radialdirection. In order to attain this result the magnets are so arrangedupon the shaft and the casing that the same poles are located oppositeeach other. For example, if a cylindrical magnet is located within thefield of a ring-shaped magnet in such manner that the same poles arelocated opposite each other, then the magnetic axes of the two magnetswill coincide automatically and by themselves, due to the repellingaction of the magnetic poles, the magnets being shifted by these forcesuntil their axes coincide. It should be noted that when the magneticaxes coincide completely and the same poles are uniformly located inrelation to each other, i. e., when the magnetic zero lines alsocoincide, then the aggregate can receive only side forces, or suchforces as are perpendicular to the magnetic axis. A slight shifting ofthe two zero lines in relation to each other, which does not influencethe automatic adjustment of the magnets in relation to the coinciding ofthe magnetic axes, produces a force component extending in the directionof the shaft which may operate against the force of gravity of avertically located shaft of a rotor, depending upon the shifting of thezero lines, whereby the force of gravity may be diminished or eliminatedentirely. This shifting of the zero lines is quite small, and is shownexaggerated in the appended drawings.

In accordance with another preferred embodiment of the inventive idea,the axis of a rotor carries sleeve-shaped magnets located at opposedends of the vertical shaft, each sleeve, or ring, magnet beingmagnetized axially and being enclosed by a ring magnet which is locatedconcentrically-thereto, and which is connected with the device, saidmagnet being also axially magnetized. This arrangement of two opposedsystems of annular magnets improves the bearing most effectively sincethen the weights of the rotary parts which operate vertically, as wellas forces exerted sidewise thereon, are practically completelycompensated so that, theoretically speaking, no mechanical bearing isrequired, and it is merely necessary to provide special guides forcentering and securing the axle. The magnetic forces, in accordance withthis invention, may be so arranged that the axially magnetized ringmagnets located upon the rotary axle and the ring magnets which arerepelled by the first-mentioned ring magnets, and which are also axiallymagnetized, are located upon the casing or framework, the two systems ofmagnets being concentrical in relation to each other. In thisconstructional form the side forces are all absorbed so that the shaftis located centrally, substantially without friction, while stepbearings are provided for the vertical forces of gravity.

In accordance with a further structural embodiment of the inventiveidea, the bearing and the centering means for rotary bodie's'ar'eimproved by adding to the axially magnetized pairs of ring magnets afurther disc-shaped annular magnet which is attached to the casing, andanother similar magnet which is attached to the shaft, the two magnetsbeing radially magnetized so that they repel each other.

This use of three magnetic systems, two of which involve axiallymagnetized magnets, while the third consists of radially magnetizedmagnets, produces a practically frictionless centering at the ends of avertical rotary axle, and an extensive balancing of the weight of therotary parts so that the shaft requires only one vertical support whichmay have the form of a cover plate upon the top end of the shaft; thisplate will receive only small forces provided that the magnetic systemsare properly adjusted.

in accordance with a further structural embodiment of the presentinvention, special requirements for bearings of horizontally locatedshafts on machines and instruments are met by concentrically combiningthree or more axially magnetized, ring-shaped permanent magnets to asingle system which is located at a suitable distance from anothercorresponding system in such manner that the same poles are locatedopposite each other. This arrangement, however, provides a certain playof the machine shaft so that it is preferable to use it only for suchmachines and instruments wherein that amount of play is permissiblebetween rotor and stator. The rotor will bend down somewhat with respectto the stator as the result of its weight, this shifting being caused bythe elasticity of the magnetic support; however, this shifting may beeasily balanced by a corresponding vertical shifting of the immovablepart of the bearing. Furthermore, additional, normal bearings may beprovided which will have for their purpose the limiting of the play to apermissible amount.

Through the use of groups of three or more axially magnetized annularpermanent magnets combined into a system, the bearings constructed inaccordance with the present invention may be employed for substantiallyheavy parts, since the repelling magnetic forces add to each other. Thishearing may be used also for machines operating with a normal number ofrevolutions, for example, acid pumps which may be driven by means of amagnetic coupling and which would not require any attention. Then themagnets must be covered by acidresisting layers.

The carrying capacity of the magnetic bearing constructed in accordancewith the present invention may be further increased by the use of doublearrangements of bearing systems whereby either the immovable or therotary parts form a single body. A plurality of such double systems,each of which consists of two systems, may be arranged upon the shaft asdesired to increase the carrying capacity thereof.

in accordance with another structural embodiment of the inventive idea,machines operating at high speeds, and having comparatively smalldiameters, may be created through the use of a magnetic hearing which isso constructed that annular, axially magnetized, permanent magnets areprovided, one next to the other, upon the sh f as weil as upon thecasing, the shaft and the casing be ig arranged stepwise, depending uponthe forces which the shaft bears. In this construction the magnets ofone body are located at a distance from each other, and are opposed tothe magnets of the other body. Furthermore, each of the steps, orstages, of the stepwise arrangement may be provided with a plurality ofring shaped systems.

It is apparent that in accordance with the present invention, magneticforces may be effectively replaced by electrostatic forces which repeleach other, and which are produced by electrically charged plates orrings consisting of electrets.

Hereinafter the terms magnetic and magne are to be construed asincluding such electrostatic forces.

In constructions wherein high speeds are essential, it is advantageousto imbed the magnets in a non-magnetic substance of great strength, suchas berylium bronze, in order to absorb the centrifugal forces.

Systems of bearings constructed in accordance with the present inventionmay be formed of uniform bearing elements in the same manner as iscustomary in conjunction with roller bearings, and such bearing systemsmay be built in the same manner.

The invention wili appear more clearly from the following detaileddescription, when taken in connection with the accompanying drawings,showing, by way of example, preferred embodiments of the inventive idea.

In the drawings:

Figure l is a diagrammatic, sectional view of a counter shaft providedwith two concentrical, axially magnetized pairs of annular magnets;

Figure 2 shows in longitudinal section a counter shaft which is centeredby two axially magnetized pairs of annular magnets located upon theshaft itself, the balancing of the weight being attained by a pair ofradially magnetized annular magnets;

Figure 3 is a longitudinal section through a bearing system, one part ofwhich is located upon the shaft while the other part is located in thecasing;

Figure 4 is a longitudinal section through a double bearing system;

Figure 5 is a longitudinal section through bearing systems provided upona stepwise shaft.

Fig. 6 is a longitudinal section through a bearing systern provided witha covered magnet.

The bearing shown in Figure 1 of the drawings is used in conjunctionwith a counter provided with a counting disc 1 which is carried upon avertical shaft 2. Two axially magnetized annular magnets 3 are firmlymounted upon the shaft 2, and are situated opposite annular magnets 4which are attached to the casing 4a (partly shown). An annular space isformed between each pair of magnets 3, 4, the magnetic field beinguniformly distributed.

A step bearing 5 is located at the top of the shaft 2 since the magneticforces create an elastic bearing for the shaft 2, so that the plate 5prevents the shaft 2 with the magnets 3 from leaving the magnetic field.The bottom of the shaft 2 is prevented from shifting vertically by afurther bearing 6.

The two bearings 5 and 6 may be shifted axially by any suitablemeans(not shown) so as to adjust the position of the shaft 2 with the magnets3 in such manner that the zero lines of the two pairs of annular magnetsalways coincide. The annular magnets 4 carried by the casing may be mademovable for the same purpose (not shown).

It is apparent that as a result of this arrangement the shaft 2 remainsin a stable equilibrium during its rotation, along with the countingdisc 1.

It is further apparent that the same poles of the magnets 3 are locatedopposite the same poles of the magnets 4, thereby producing therepelling forces.

Annular guides 17 are located at opposite ends of the shaft 2. Theseguides do not engage the shaft 2 in operation, but serve as stopspreventing excessive axial shiftmg.

In the construction shown in Figure 2, the vertical shaft 7 of acounting instrument carries annular axially magnetized magnets 8 and 11.An annular axially magnetized magnet 9 is located opposite the magnet 8.Similarly, an axially magnetized magnet 10 is located opposite themagnet 11, and is attached to the casing 10a (partly shown).

The shaft 7 also carries an annular magnet 12 which is firmly mountedupon the shaft by means of an intermediate support 13 consisting of anonmagnetic material. Another annular magnet 14 which is similar in formto the magnet 12 is located below the magnet 12, and is attached to thecasing.

The magnets 12 and 14 are magnetized radially, and their poles are soarranged that they repel each other, thereby compensating to asubstantial extent the vertical forces exerted upon the rotary parts ofthe instrument and produced mainly by the weight of these rotary parts.

A hearing 15 is provided at the top of the shaft 7, while a plate 16 isprovided at the bottom of the shaft to limit the downward movementthereof.

It is apparent that the construction of Figure 2 includes opposedaxially magnetized pairs of magnets 8, 9 and 11, 10, as well as radiallymagnetized magnets 12, 14, all of said magnets having the same poleswhich oppose each other and, therefore, provide repelling forces.

The device is also provided with rings or guides 17 which are similar inconstruction and function to the guides 17 shown in Figure l.

The construction shown in Figure 3 consists of a machine having a casing18 and a rotary shaft 18a carrying a rotor 18b. The magnetic bearingconsists of systems 19 and 19a. The system 19 is immovable and consistsof three concentrical, annular, permanent magnets 20, 21 and 22, whichare magnetized in the direction of the shaft 18a and which are locatedat suitable distances from each other upon a support 19 carried by thecasing 18. Rotary magnets 24 and 25 are located in the spaces betweenthe magnets 20, 21 and 22. The magnets 24 and 25 are similar inconstruction to the magnets 20, 21 and 22, and are integral with acarrier 23, thus constituting a system 19a which is located opposite thesystem 19. The magnets 24 and 25 are also magnetized in the direction ofthe shaft 18a so that repelling forces are created between the magnets20, 21 and 22, on the one hand, and the magnets 24 and 25, on the otherhand.

It is apparent that the described bearing consists of two magneticsystems which make it possible to employ the bearing for fairly heavyrotary parts.

The construction shown in Figure 4 includes the machine casing 30acarrying a support 30, which is firmly connected therewith. The support30 is integral, or firmly connected, with annular magnets 31, 32 and 33,which are disposed concentrically. Rotary annular magnets 27, 28 and 29are located in the spaces between the magnets 31, 32 and 33. The magnets27, 28 and 29 are connected to, or integral with, a support 34 which iskeyed upon the shaft 34a. Thus, the shaft 34a rotates along with themagnets 27, 28 and 29 in relation to the magnets 31, 32 and 33 of thecasing 30a. The magnets are so disposed that their poles repel eachother. In other respects the construction is similar to those alreadydescribed.

It is apparent that a concentrical arrangement of the annular magnetsincreases the diameter of the machine. In the construction shown inFigure 5 the magnets are located side by side, thereby eliminating thisdrawback. A shaft 38, having sections of different diameters, carriesannular magnets 35, 36 and 37. Magnets 39, 40 and 41 are concentrical inrelation to the magnets 35, 36 and 37, and are located opposite theretowith the same poles located opposite each other. The magnets 39, 40 and41 are firmly mounted in the immovable casing 42, which corresponds inshape to that of the shaft 38. The casing 42 is carried by the machineframe.

This construction is most suitable for high speed rotary parts, and issimilar in operation to those already described.

In the construction shown in Fig. 6 an annular magnet 44 is firmlymounted upon the shaft 43 and is enclosed by a ring 45 consisting of anon-magnetic material. The opposed ring 46 consists of permanentmagnetic steel and is firmly mounted in the support 47.

The following principles are to be considered in the manufacture of allthe above-described embodiments of the inventive idea:

As is well known, practically all magnetic substances create magneticfields, the strength of which is not absolutely uniform as a result ofvariations in the degree of magnetizing, lack of homogeneity of thesubstance itself, etc. This lack of uniformity can create lossesproduced by eddy currents, particularly when the machine is operatedwith a high number of revolutions. It is, therefore, advantageous to usesuch permanent, magnetical substances which are made from comminuted,permanently magnetic material held by an insulating binder.

It is particularly suitable to employ permanently magnetic substances ofsmall permeability, the coercive force of which is higher, however, than300 oersted.

This selection of the material is caused by the fact that with anincrease in the coercive force and smaller permeability the magneticlosses are diminished.

It is apparent that the specific illustrations given above have beenshown by way of illustration and not by way of limitation, and that theyare subject to wide variations and modifications without departing fromthe scope or intent of the invention, all of which variations andmodifications are to be included within the scope of the presentinvention.

The term tensile strength as used in the specification and claims isintended to designate the resistance of a material to tear action by aload.

What is claimed is:

l. A bearing for instruments and machines, comprising a rotary shaft, acasing at least partly enclosing said shaft, at least one mechanicalsupport for said shaft, a cylindrical axially magnetized permanentmagnet mounted upon said shaft and rotatable therewith, and a secondcylindrical axially magnetized permanent magnet firmly mounted upon saidcasing concentrically to the firstmentioned magnet and enclosing thefirst-mentioned magnet, said magnets having poles of the same polaritylocated opposite each other, whereby the magnets repel each other, and aring of non-magnetic material of high tensile strength which enclosesthe first-mentioned magnet.

2. A hearing for instruments and machines, comprising a rotary shaft, acasing at least partly enclosing said shaft, at least one mechanicalsupport for said shaft, a carrier connected with said shaft, a pluralityof cylindrical axially magnetized permanent magnets concentricallysupported upon said shaft by said carrier in spaced relationship to eachother and enclosing each other, said magnets and said carrier rotatingalong with said shaft, and a corresponding number of other cylindricalaxially magnetized magnets enclosing each other and concentricallymounted in spaced relationship upon said casing, the first-mentionedmagnets extending into the spaces between said other magnets, the twogroups of magnets having poles of the same polarity located oppositeeach other, whereby magnets of one group repel magnets of the othergroup.

3. A hearing for instruments and machines, comprising a rotary shaft, acasing at least partly enclosing said shaft, at least one mechanicalsupport for said shaft, a carrier connected with said shaft, a pair ofgroups of permanent magnets supported next to each other axially uponsaid shaft by said carrier, each of said groups comprising a pluralityof cylindrical concentrical axially magnetized permanent magnetsdisposed in spaced relationship to each other and enclosing each other,said magnets and said carrier rotating along with said shaft, andanother pair of groups of permanent magnets mounted adjacent to eachother axially upon said casing, each of said other groups comprising aplurality of cylindrical concentrical axially magnetized permanentmagnets disposed in spaced relationship to each other and enclosing eachother, the magnets of the first-mentioned pair of groups extending intothe spaces between the magnets of said other pair of groups, the twopairs of groups of magnets having poles of the same polarity locatedopposite each other, whereby magnets of one pair of groups repel magnetsof the other pair of groups.

4. A bearing for instruments and machines, comprising a rotary shaft, acasing at least partly enclosing said shaft, at least one mechanicalsupport for said shaft, a plurality of cylindrical axially magnetizedpermanent magnets mounted upon said shaft and spaced axially thereon,said magnets rotating along with said shaft, and an equal number ofother cylindrical axially magnetized permanent magnets concentricallyenclosing the firstmentioned magnets and equally spaced from each other,said other magnets being mounted in said casing, the two poles of allmagnets repelling each other, said shaft and said casing consisting ofsections of dilferent diameters.

References Cited in the file of this patent UNITED STATES PATENTS HansenSept. 2, 1941 Schug Mar. 2, 1948 Sturtevant et al. July 10, 1951Guillaud Nov. 27, 1951 Goldsmith Mar. 15, 1955 FOREIGN PATENTS GreatBritain Sept. 9, 1941 Great Britain Aug. 30, 1950

